Sheet holder

ABSTRACT

An improved sheet holder having a substantially rigid base plate and a clamping member hingedly connected to the base plate along one edge thereof for clamping engagement with one edge of a sheet for securely maintaining same in position adjacent the upper surface of the base plate. A substantially channel-shaped hinge member is fixedly secured to the base plate and extends into substantially parallel slots formed in the clamping member for permitting relative pivotal movement therebetween. A leaf spring is disposed between the legs of the hinge member and is positioned to resiliently urge the clamping member toward an open or closed position. The hinge assembly, including the spring, is substantially hidden by the clamping member, even when in the open position.

United States Patent 1191 Dixon SHEET HOLDER {75] Inventor: Allen L. Dixon, Portage, Mich.

[73] Assignee: Master-Craft Corporation,

Kalamazoo, Mich.

[221 Filed: Sept. 20, 1971 [21] App]. No.: 181,798

[52] US. Cl. 282/29 B, 402/69 [51] Int. Cl. B411 3/04 [58] Field of Search 282/29 R, 29 A, 29 B; 402/60, 69, 70; 24/67.3, 67.5, 67.7; 281/45 R [56] References Cited UNITED STATES PATENTS 2,338,532 l/1944 Page 282/29 B 1,844,744 2/1932 Critchfield.... 281/45 X 3,291,505 12/1966 Bell et a1. 282/29 B 555,289 2/1896 McGinty 402/69 X 2,486,253 10/1949 Bresler 24/67.7 3,310,901 3/1967 Sarkisian 24/67.7 X

1451 Aug. 14, 1973 Primary Examiner.lerome Schnall Attorney-Woodhams, Blanchard and Flynn [57] ABSTRACT An improved sheet holder having a substantially rigid base plate and a clamping member hingedly connected to the base plate along one edge thereof for clamping engagement with one edge of a sheet for securely maintaining same in position adjacent the upper surface of the base plate. A substantially channel-shaped hinge member is fixedly secured to the base plate and extends into substantially parallel slots formed in the clamping member for permitting relative pivotal movement therebetween. A leaf spring is disposed between the legs of the hinge member and is positioned to resiliently urge the clamping member toward an open or closedv position. The hinge assembly, including the spring, is substantially hidden by the clamping member, even when in the open position.

10 Claims, 6 Drawing Figures PAIENTED M19 4 I913 SHEE'I 1 0F 2 INVEN TOR. Alli/V 1. 0/104 PAIENIEB m 34 III! SHEET 2 BF 2 ha M 30%.

SHEET HOLDER FIELD OF THE INVENTION This invention relates to a binder and, in particular, to an improved binder of the type commonly referred to as a sheet holder.

BACKGROUND OF THE INVENTION Various types of sheet holders have been devised and are widely used for permitting a small number of sheets to be conveniently and safely stored in a portable device while at the same time providing a substantially rigid support surface for the sheets. Such sheet holders generally comprise a substantially rigid base plate having an upper support surface adapted to have one or more sheets disposed thereon, which sheets often have a plurality of holes along one edge thereof adapted to coact with a plurality of pins secured to one edge of the 1 base plate for retaining the sheets on the base plate. The sheet holder also has an elongated clamping member pivotally connected to the base plate along one edge thereof, which clamping member is swingable into a closed clamping position wherein it overlies the pins and engages the sheets to prevent the edges of the sheets from becoming dislodged from the pins. The clamping member is swingably movable into an open position to uncover the pins and to permit the sheets to be readily removed therefrom, which swinging movement between the open and closed positions is normally assisted by an over-center spring device.

While the known sheet holders have generally operated in a satisfactory manner, nevertheless it has been discovered that the hinge and spring arrangement of many of the known sheet holders has resulted in operational inconveniences and disadvantages. Particularly, most of the sheet holders of which I am aware have utilized conventional coil springs connected between the base plate and the clamping member for resiliently urging the clamping member to either its open or closed positions. These coil spring members are generally disposed within enlarged recesses formed in the clamping member, which recesses are normally fully exposed when the clamping member is in the open position. This structure necessarily destroys the desirable appearance of the sheet holder. Further, it has been discovered that these recesses tend to collect dirt therein, which thus restricts the free deflection of the spring and at the same time results in dirt or other undesired particles being accidentally deposited on the sheets. This problem of dirt and the like collecting within the recesses is particularly pronounced in situations where corrections are made on the sheets, such as by using an eraser, whereupon the particles of the eraser tend to collect in the recesses.

Still a further disadvantage of the known sheet holders has been their mechanical complexity. The prior known devices have utilized hinge and spring structures coacting between the base plate and the clamping member which have been unnecessarily complex. This has thus increased both the manufacturing and assembly costs.

Accordingly, it is an object of the present invention to provide an improved sheet holder which overcomes the above mentioned disadvantages. Particularly, it is an object of the present invention to provide:

I. An improved sheet holder having an improved hinge and spring arrangement coacting between the clamping member and the base plate.

2. A sheet holder, as aforesaid, utilizing leaf springs arranged to pass through an over-center position to thus resiliently urge the clamping member toward the open and closed positions.

3. A sheet holder, as aforesaid, utilizing U-shaped hinge members which project into narrow slots formed in the clamping member to thus be substantially hidden and thereby provide an attractive appearance when the clamping member is in both the open and closed positions.

4. A sheet holder, as aforesaid, wherein a leaf spring is disposed within the U-shaped hinge member and is positioned so that there is little possibility for dirt and other contaminating particles to collect therearound.

5. A sheet holder, as aforesaid, which is of simple but durable construction, which is pleasing in appearance, and which is easy and efficient to utilize.

6. A sheet holder, as aforesaid, which can be constructed utilizing elongated members which can be easily and economically extruded from materials having a desirable appearance, such as aluminum, and which members can be designed to not only have a desirable appearance but also have a suitable configuration to permit same to function as a clamping member disposed for swinging movement between a closed clamping position disposed adjacent the base and an open release position disposed in abutting engagement with the edge of the base plate.

Other objects and purposes of the present invention will be apparent to persons acquainted with devices of this type upon reading the following specifications and inspecting the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sheet holder constructed according to the present invention, same being illustrated with the cover in the closed position.

FIG. 2 is a fragmentary perspective view similar to FIG. 1 but illustrating therein both the cover and the clamping member in the open position.

F IG. 3 is a fragmentary sectional view taken substantially along the line III-III of FIG. 1 and illustrating the clamping member in the closed position.

FIG. 4 is a fragmentary sectional view taken substantially along the line IV--IV of FIG. 2 and illustrating the clamping member in the open position.

FIG. 5 is a fragmentary sectional view taken substantially along the line V-V of FIG. 3.

FIG. 6 is an exploded perspective view of the sheet holder according to the present invention.

Certain terminology will be used in the following description for convenience in reference only and will not be limiting. The words upwardly," downwardly, rightwardly," and leftwardly will refer to directions in the drawings to which reference is made. The words inwardly" and outwardly will refer to directions toward and away from, respectively, the geometric center of the device and designated parts thereof. Said terminology will include the words above specif cally mentioned, derivatives thereof, and words of similar import.

SUMMARY OF THE INVENTION The objects and purposes of the present invention are met by providing a substantially rigid base plate adapted to have a small number of sheets disposed thereon, which base plate has an elongated base member fixedly secured along one edge thereof. A plurality of upright pins adapted to extend through perforations formed in the sheets are used for fixedly connecting the base plate to the base member. An elongated channelshaped clamping member is hingedly connected to the base member and is swingably movable between an open position permitting access to the pins, and a closed position covering the pins. In the closed position, the edge of the clamping member engages the sheets along one edge thereof to maintain said sheets securely on the base plate. The base member has mounted thereon a pair of upstanding U-shaped hinge members, the legs of which extend in narrow slots formed in one leg of the clamping member. Leaf springs are preferably disposed between the legs of the hinge members and resiliently coact with the one leg of the clamping member. The leaf springs are movable through an over-center position when the clamping member moves between its closed and opened positions to thus resiliently urge the clamping member toward its opposite end positions. The clamping member is additionally preferably provided with a laterally offset flange which functions both as a manual gripping flange to facilitate opening of the clamping member and as a stop member to limit the opening movement. The sheet holder may, if desired, be provided with an elongated stripper hingedly supported on the hinge members and adapted to be disposed within a recess defined by the channel-shaped clamping member when in the closed position. The stripper is substantially L- shaped in cross section and has one leg adapted to be disposed under the sheets in the direct vicinity of the pins, whereby pivotal swinging movement of the stripper causes the sheets to be moved upwardly off the pins. The sheet holder may also be provided with a suitable cover adapted to overlie the base plate to protect the sheets thereon, which cover is hingedly connected to the base plate along the edge thereof opposite the clamping member.

DETAILED DESCRIPTION The drawings illustrate therein a sheet holder 1 1 constructed according to the present invention. The sheet holder 11 includes a base portion 12 adapted to have a number of sheets disposed thereon. A releasable clamping means 13 is disposed adjacent one edge of the base portion 12 for permitting one edge of the sheets to be releasably secured to the base portion. The sheeti holder 11 may also be provided, if desired, with a swingable cover portion 14 which, when in the position illustrated in FIG. 1, overlies the base portion 12 to thus cover and protect the sheets held within the holder.

The base portion 12 includes a substantially rigid and rectangular base plate 16 which preferably has a resilient pad 17 secured to the bottom surface thereof. The pad 17, in the illustrated embodiment, is totally enclosed within a sheet of plastic 18, which sheet on its upper surface is secured, as by an adhesive, to the underside of the base plate 16.

The cover portion 14 is constructed in a similar manner to the base portion 12 and includes a rigid and substantially rectangular support plate 19 having a resilient pad 21 secured to the outer surface thereof, which pad 21 is also preferably enclosed by a suitable sheet of plastic 22. The sheet of plastic 22 is also preferably adhesively secured to the support plate 19.

The base plate 16 and support plate 19 are constructed of any suitable rigid material, such as aluminum, to thus provide substantially rigid surfaces which will totally protect the sheets when the holder is in the closed position. The base plate 16 also provides a rigid support surface to permit writing on the sheets when the holder is in the open position.

The holder 11 is also provided with a hinge structure for interconnecting the base portion and the cover portion, which hinge structure in the illustrated embodiment specifically includes an intermediate portion 23 integrally connected to the plastic sheets 18 and 24 to thus define a strap-like hinge. The sheet 18 may also be provided with a flap portion 24 along an edge thereof for securement to the underside of the below-described base member 26.

The base portion 12 includes an elongated base member 26 extending longitudinally along one edge of the base plate 16. The base member 26 has a plurality of openings 27 therein, which openings are disposed in a row extending longitudinally of the member and are substantially aligned with a similar row of openings 28 formed along the edge of the base plate 16. The openings 27 and 28 are adapted to be aligned and a plurality of stepped pins 29 extend through the aligned openings for fixedly securing the edge of the base plate 16 to the base member 26. The edge of the base plate 16 is disposed in overlapping relationship with the base member 26, with the edge of the base plate 16 being substantially abutted against a shoulder defined by an elongated rib 31 which projects upwardly of the base member 26 and extends longitudinally thereof. The rib 31 is substantially centrally disposed on the upper surface of the base member 26. The opposite longitudinal edge of the base member 26 has an upwardly projecting flange 32 extending therealong, which flange 32 is laterally spaced from but substantially parallel to the rib 31.

The base member 26 has a pair of substantially U- shaped hinge members 33 fixedly secured thereto, which hinge members are disposed adjacent the opposite ends of the base member. Each hinge member 33 specifically includes a support plate 34 having a pair of openings 36 therethrough which are adapted to align with similar openings 37 formed in the base member 26. A screw 38, such as a self tapping screw, and a screw 39 are adapted to extend through the aligned openings 36 and 37 for fixedly securing the support plate 34 to the base member 26. The fixing of the support plate to the base member, as explained above, results in the hinge members being disposed in the space between the rib 31 and the flange 32.

Each hinge member 33 also includes a pair of substantially parallel hinge plates 41 and 42 extending upwardly from the opposite edges of the support plate 34. The hinge plate 41 has an opening 43 therethrough, and the hinge plate 42 has an elongated slot 44 formed therein, the inner end of the slot 44 being substantially aligned with the opening 43 for a purpose to be explained hereinafter.

Considering now the releasable clamping means 13, same includes an elongated clamping member 46 which, as illustrated in F IG. 3, has a substantially downwardly directed channel-shaped configuration. The

clamping member 46 specifically includes opposite flange portions 47 and 48, hereinafter respectively referred to as the clamping flange portion and the hinge flange portion, fixedly connected to a center portion 49. The clamping'flange portion 47 has an elongated recess 51 formed in the free end thereof, which recess receives therein a portion of a resilient rubber-like clamping strip 52. The clamping strip 52 projects beyond the free end of the clamping flange portion and, when the clamping member 46 is in the closed position illustrated in FIG. 3, is disposed for engagement with the base plate 16 (or the sheets disposed thereon) at a position disposed adjacent but slightly outwardly of the mounting pins 29, as illustrated by dotted lines in FIG. 4.

The hinge flange portion 48 is provided with a pair of narrow, substantially parallel slots 53 and 54 formed therein adjacent the opposite ends thereof, which slots 53 and 54 are adapted to respectively receive therein the hinge plates 41 and 42. The hinge flange portion 48 also has an elongated, longitudinally extending bore 56 formed in each end thereof, which bore 56 is adapted to align with the opening 43 and the inner end of the slot 44. A hollow, axially split spring pin 57 is disposed within each bore 56 and is resiliently fixedly held therein, the pin 57 being disposed so as to extend across the slot 54 whereby the pin 57 thus extends through the inner end of the slot 44 for hingedly connecting the clamping member 46 to the stationary hinge members 33. The outer ends of the spring pins 57, however, are displaced inwardly from the ends of the flange portion 48 so that the spring pins 57 do not extend across the slots 53. A suitable screw 58, such as a self tapping screw, extends into the outer end of each bore 56, with the screw 58 having a length sufficient to extend across the slot 53 whereby the screw 58 thus extends through the opening 43 formed in the hinge plate 41 to still further hingedly connect the clamping member 46 to the stationary hinge members 33.

The clamping member 46 also has a laterally offset flange 59 which substantially constitutes an extension of one end of the center portion 49. However, the flange 59 extends outwardly beyond the hinge flange portion 48 and is laterally offset upwardly relative to the center portion 49 when the clamping member is in the closed position illustrated in FIG. 3. The flange 59 has an upper surface 61 which is preferably serrated or roughened to thus permit the thumb or fingers of the user to grip same and thus exert a force for moving the clamping member from the closed position of FIG. 3 into the opened position of FIG. 4. The underside of the flange 51 is interconnected to the hinge portion 48 by an intermediate concave surface 62, which surface accommodates therein the upwardly projecting flange 32 when the clamping member 46 is moved to the open position illustrated in FIG. 4. The underside of the flange 59 abuts against the outer surface of the flange 32 when the clamping member is in the open position, whereby the flange 59 thus functions as a stop member for limiting the opening movement of the clamping member.

Each of the hinge member 33 has a cantilevered plate-like leaf spring 63 associated therewith for coacting between the clamping member 46 and the base member 26 to thus resiliently urge the clamping member toward either its open position or its closed position. The leaf spring 63 specifically includes a mounting portion 64 which is positioned between the hinge plates 41 and 42 and is fixedly secured relative to the base member 26 by means of the screw 38. The leaf spring 63, when mounted on the base member 26, projects rearwardly and upwardly so as to be normally resiliently but slidably engaged with a contoured cam surface 66 as formed on the free end of the hinge flange portion 48. The cam surface 66 is contoured such that it causes the spring 63 to pass through an over-center" position as the clamping member is moved between its open and closed positions. That is, when the clamping member 46 is in the closed position illustrated in FIG. 3, the leaf spring 63 engages the cam surface 66 at a location such that the spring exerts a resilient torque on the clamping member 46 tending to move same in a clockwise direction about the hinge pins 57, whereby the springs 63 thus cause the clamping member to be maintained in its closed position. However, as the clamping member is moved toward its open position, the force exerted on the clamping member by the springs 63 shifts unto the opposite side of the axis defined by the hinge pins 57 so that the springs thus exert a counterclockwise resilient torque on the clamping member so as to resiliently maintain same in the open position illustrated in FIG. 4.

Each hinge plate 41 as formed on the hinge member 33 is elongated so as to project forwardly through the slot 53, as illustrated in FIG. 2. The forward end of the hinge plate 41 has a further opening 67 formed therein, which opening receives therein one end of a hollow, axially split spring pin 68, which spring pin is fixedly secured within a further opening 69 formed within one end of an elongated stripper member 71. The stripper member 71 has a substantially L-shaped cross section and is elongated in a direction substantially parallel to the clamping member 46. The stripper member 71 extends between the opposed hinge plates 42, and illustrated in FIG. 2, and is positioned so as to be disposed within and totally enclosed by the downwardly directed channel-shaped clamping member 46 when same is in the closed position illustrated in FIG. 3. The stripper member 71 includes substantially transverse leg portions 72 and 73. The leg portion 72 is enlarged to receive therein the split hinge pin 68, the axis of which is spaced upwardly from the leg portion 73. The leg portion 73 is constructed as a thin plate-like member and has a plurality of small notches or recesses 74 formed along the free edge thereof, which notches are adapted to receive therein the row of pins 29 when the stripper member is in its normal position as illustrated in FIGS. 2-4. The plate-like leg portion 73 is normally disposed directly under the edges of the sheets disposed on the base plate 16 so that when the clamping member is swingably moved into its open position, as illustrated in FIG. 4, the stripper member 73 can likewise be manually swingably moved into the dotted line position illustrated in FIG. 4, which swinging movement results in the perforated edges of the sheets being lifted upwardly off the pins 29 to thus release the sheets from the holder 11.

A pair of plate-like end covers 76 are disposed adjacent the opposite ends of the clamping member 46 for substantially closing the channel or recess defined therein when the clamping member is in the closed position. The end covers 76 have a configuration which approximates the exterior configuration of the clamping member 46, and are provided with a pair of openings 77 along the bottom edge thereof, which openings align with similar openings 78 formed in the end of the base member 26. Suitable screws 79, such as self tapping sheet metal screws, extend through the aligned openings 77 and 78 for fixedly securing the end covers 76 to the opposite ends of the base member 26. The end covers also have a narrow slot 81 formed therein, which slot projects inwardly from the front edge of the sheet holder and is disposed directly adjacent the upper surface of the base plate 16, whereby the slots 81 thus accommodate therein the free edge of a sheet in situations where the sheet has a height greater than the height of the base plate 16.

If desired, an elongated flexible strip 82, such as a vinyl strip, can be secured, as by an adhesive, to the upper surface of the clamping member 46. The strip 82 can be used either for decorative purposes or can be provided with suitable indicia or markings thereon.

It should also be noted that the cover portion 14, as illustrated in FIG. 3, has a flange 83 formed along the free edge thereof, which flange is adapted to be disposed under the clamping strip 52 when the cover portion 14 is in its closed position and the clamping member 46 is also in its closed position. The clamping member 46 thus engages the flange 83 and accordingly resiliently maintains the cover portion 14 in its closed position.

OPERATION To operate the sheet holder 11, and assuming that the sheet holder is initially in the closed position illustrated in FIGS. 1 and 3, the clamping member 46 is pivoted to its open position by exerting a downward pressing force on the surface 61, which force rotates the clamping member 46 counterclockwise about the hinge pins 56. As the clamping member 46 moves counterclockwise, the springs 63 pass through an over-center position so that the latter part of the counterclockwise movement of clamping member 46 is assisted by the resilient urging of the springs 63, which springs 63 cause the stop flange 59 to abut against the flange 32. Springs 63 thus resiliently maintain the clamping member 46 in the open position of FIG. 4. The cover portion 14 can then be moved into its open position to expose the base plate 16. One or more suitable sheets or papers are then positioned on the base plate 16 with the perforated edges of the sheets being disposed so as to register with the plurality of pins 29, the sheets being disposed so that the leftward edges thereof register with the pins 29 and overlie the leg portion 73 of the stripper member 71. The clamping member 46 is then returned to its closed position by means of a manual pressing force being exerted thereon, such as adjacent the clamping flange portion 47. The pressing force initially overcomes the resilient urging of the springs 63 and accordingly moves the clamping member clockwise about the hinge pins 57. As the clamping member is moved clockwise toward its closed position, the springs 63 again pass through their over-center position and exert a clockwise resilient torque on the clamping member to resiliently urge the clamping member toward its closed position. When the clamping member 46 is in its closed position, the clamping strip 52 assumes the position illustrated by dotted lines in FIG. 4, whereupon it clampingly engages the sheets at a location disposed directly adjacent but outwardly of the pins 29. The clamping member thus maintains the edges of the sheets firmly on the pins and likewise maintains the sheets clampingly engaged with the base plate 16. The sheets as mounted on the base plate 16 are thus in a position to be utilized, whereupon the user of the sheet holder can accordingly write or perform other desired operations on the sheets.

After the desired operations have been performed on the sheets, but it is still desired to maintain the sheets within the holder, then the cover portion 14 can be pivoted to its closed position. When the cover approaches its fully closed position, as illustrated in FIG. 1, the clamping member 46 must be manually depressed to pivotally move same slightly away from its fully closed position. This permits the flange 83 to pass by the free edge of the clamping member, whereupon the clamping member can then again be resiliently returned to its closed position so that the clamping strip 52 is resiliently maintained in clamping engagement with the flange 83. The clamping member 46 thus resiliently maintains the cover 14 in its closed position, which in turn both protects the sheets and maintains the sheets securely positioned on the base portion.

Alternately, when it is desired to remove the sheets from the holder 11, and assuming that the cover por tion 14 is in its open position, then the clamping member 46 is again moved into the open position illustrated in FIG. 4. The stripper member 72 is then manually piv oted in a counterclockwise direction to assume the po' sition illustrated by dotted lines in FIG. 4. This pivoting of the stripper 71 causes the leg portion 73 to move upwardly along and beyond the pins 29, which thus causes the edges of the sheets to be raised upwardly off of the pins 29 whereby the sheets can then be removed from the holder.

In the construction of the holder 11, the base member 26 and the clamping member 46 are each preferably integrally constructed as one piece, such as by being extruded from aluminum, whereby the members thus have the desired structural characteristics and shape, while at the same time the members have an appearance which is desirable due to the structural and functional characteristics which it possesses, and also due to the pleasing appearance which it presents.

While the sheet holder 11 in the illustrated embodiment is provided with a swingable cover portion 14, it will be recognized that in many use situations such a cover portion is not necessary and accordingly can be omitted. Further, while the disclosed embodiment illustrates a large number of aligned pins 29, the number of pins utilized will depend upon the type of sheets being used in conjunction with the holder. Thus, in many situations the sheets utilized possess only a pair of holes, with one hole being disposed adjacent each corner of the sheet. In this situation the holder need be provided with only a pair of pins, rather than with a large number of pins as illustrated. In this situation some of the pins 29 can then be replaced with conventional rivots to fixedly secure the base plate 16 to the base member 26. In situations where only a small number of pins 29 are used, then removal of the sheets from the pins is generally a much simpler operation, in which case the stripper member 71 may also be omitted.

A further desirable feature of the present invention is the manner in which the above-described hinge structure facilitates both the assembly or disassembly of the clamping member 46 and the base member 26. Considering first the assembly operation, and assuming that the split spring pins 57 have been properly positioned within the bores 56 so as to extend across the slots 54, and assuming also that the hinge members 33 have been fixedly secured to the base member 26, then i the clamping member 46 can be readily connected to the base member 26 merely by inserting the hinge plates 41 and 42 into the slots 53 and 54, respectively. This inserting operation is accomplished by first positioning the hinge flange portion 48 rearwardly (leftwardly in FIGS. 3 and 4) of the hinge plates so that the hinge pins 57 are substantially aligned with the free end of the slots 44. The clamping member is then moved so that the plates 41 and 42 enter into the slots 53 and 54, which movement continues until the pins 57 are disposed within the inner end of the slots 44. In this position, the opening 43 in hinge plate 41 is now aligned with the bore 56, whereupon the screws 58 can be inserted into the bores so as to extend through the openings 43, thereby maintaining the hinge pins 57 property positioned within the inner end of the slots 44 and preventing the clamping member 46 from being accidentally disconnected from the base member 26. The disassembly of the clamping member 46 from the base member 26 will obviously be performed in the reverse manner.

Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A holder adapted to releasably hold a small number of sheets having opening means along one edge thereof, comprising:

base means including a substantially rigid plate-like member adapted to have said sheets supported on the upper surface thereof, said base means also including an elongated base member disposed adjacent and fixedly connected .to one edge of said plate-like member;

pin means fixedly secured to said base means adjacent said one edge of said plate-like member and projecting upwardly from said upper surface, said pin means being adapted to extend through the opening means formed in said sheets;

clamping means mounted on said base means for releasably holding said sheets in engagement with said pin means, said clamping means including an elongated clamping member disposed adjacent and substantially parallel to said base member;

hinge means connected between said clamping member and said base means for permitting said clamping member to be pivotally moved between (1) a closed position wherein the clamping member holds the sheets in engagement with the pin means and (2) an open position permitting the sheets to be removed from the pin means:

said clamping member having a substantially channel-shaped cross section which opens downwardly toward said upper surface and extends over said pin means when the clamping member is in said closed position, said clamping member including opposed and substantially parallel leg portionsextending longitudinally thereof, one of said leg porm tions being connected to said hinge means, the other leg portion comprising the free edge of said clamping member and having a deformable clamping strip secured thereto for clamping engagement with the sheets at a position directly adjacent said pin means when the clamping member is in said closed position, said clamping member also having a pair of closely adjacent but laterally spaced narrow slots formed in the free end of said one leg portion', said hinge means including a substantially U-shaped hinge member having a center portion thereof fixedly connected to said base means and a pair of substantially parallel hinge plates disposed within planes substantially transverse to the elongated direction of said clamping member, said hinge plates being disposed within said slots, and said hinge means also including hinge pin means connected between said hinge plates and said one leg portion;

said hinge pin means including a first pin member disposed within a bore formed in said one leg portion, said first pin member extending across one of said slots, and one of said hinge plates having a slot formed therein and open to an edge thereof with said one hinge plate being adapted to extend into said one slot for hingedly connecting said clamping member to said base means while permitting dis,- connection therebetween without requiring removal of said first pin member from said clamping member, said hinge means also including a second pin member mounted on said one leg portion of said clamping member and extending across the other slot, said second pin member extending through an opening formed in the other hinge plate for preventing disconnection of said clamping member and said base member; and

over-center spring means including a plate-like leaf spring coacting between said clamping member and said base means for resiliently maintaining said clamping member in both said positions.

2. A holder according to claim 1, wherein said leaf spring is of a cantilevered type and is disposed within the U-shaped hinge member between said pair of hinge plates.

3. A holder according to claim 2, wherein said leaf spring has one end thereof positioned directly adjacent the ,center portion of said U-shaped hinge member and fixedly interconnected to said base member, the other end of said leaf spring being free and being disposed in resilient engagement with the free end of said one leg portion of said clamping member.

4. A holder according to claim 1, wherein said base member has an elongated flange fixedly secured to the free edge thereof and projecting longitudinally of said base member, and said clamping member having an elongated flange projecting outwardly from the center portion thereof adjacent the junction with saidone leg portion,-said elongated flange being interconnected to said one leg portion by means of an undercut concave surface, said elongated flange on said clamping memberfunctioning as a stop member and being disposed in abutting engagement with the upwardly directed flange on the edge of said base member when said clamping member is in said open positiomthe upwardly directed flange on said base member extending toward said one leg portion and being disposed in substantial engagement with said concave surface when said clamping member is in said open position.

5. A holder according to claim 1, further including a pair of removable plate-like cover members fixedly but removably secured to the opposite ends of said base member, said cover members being disposed directly adjacent the opposite ends of said clamping member and projecting upwardly to substantially close the opposite ends of the recess defined by the downwardly directed channel-shaped clamping member when the clamping member is in the closed position.

6. A holder according to claim 1, wherein the elongated base member and the elongated clamping member are both extruded from aluminum.

7. A holder according to claim 1, wherein the base member includes an upwardly projecting rib extending longitudinally thereof, said rib being disposed substantially midway between the opposite longitudinal edges of said base member, said base member further having an upwardly directed flange extending longitudinally along one edge thereof;

said hinge means including a pair of said U-shaped hinge members fixedly secuted to said base member adjacent the opposite ends thereof, said U- shaped hinge members being disposed in engagement with the upper surface of said base member in the region defined between said rib and said upwardly projecting flange; and

said plate-like member overlapping the upper surface of said base member with the edge of said plate-like member being disposed substantially in abutting engagement with said rib.

8. A holder according to claim 1, wherein said base means includes a resilient pad fixedly secured to the bottom surface of said plate-like member, and cover means hingedly connected to said base means along the longitudinal edge thereof opposite said clamping member, said cover means being swingably movable into a position wherein it overlies said plate-like member for substantially covering same.

9. A holder according to claim 1, wherein said first pin member comprises a hollow axially split spring pin.

10. A holder adapted to releasably hold a small number of sheets having opening means along one edge thereof, comprising:

base means including a substantially rigid plate-like member adapted to have said sheets supported on the upper surface thereof, said base means also including an elongated base member disposed adjacent and fixedly connected to one edge of said plate-like member;

clamping means mounted on said base means for releasably holding said sheets in engagement with said plate-like member, said clamping means including an elongated clamping member disposed adjacent and substantially parallel to said base member;

hinge means connected between said clamping member and said base means for permitting said clamping member to be pivotally moved between (1) a closed position wherein the clamping member holds the sheets in engagement with the plate-like member and (2) an open position permitting the sheets to be removed from the base means;

said clamping member having a substantially channel-shaped cross section which opens downwardly toward said upper surface when the clamping member is in said closed position, said clamping member including opposed and substantially parallel leg portions extending longitudinally thereof, one of said leg portions being connected to said hinge means, the other leg portion comprising the free edge of said clamping member and having a clamping strip for clamping engagement with the sheets when the clamping member is in said closed position, said clamping member also having a pair of closely adjacent but laterally spaced narrow slots formed in the free end of said one leg portion;

said hinge means including a substantially U-shaped said hinge pin means including a first pin member disposed within a bore formed in said one leg portion, said first pin member extending across one of said slots, and one of said hinge plates having a slot formed therein and open to an edge thereof with said one hinge plate being adapted to extend into said one slot for hingedly connecting said clamping member to said base means while permitting disconnection therebetween without requiring removal of said first pin member from said clamping member, said hinge means also including a second pin member mounted on said one leg portion of said clamping member and extending across the other slot, said second pin member extending through an opening formed in the other hinge plate for preventing disconnection of said clamping member and said base member; and

over-center spring means including a plate-like leaf spring coacting between said clamping member and said base means for resiliently maintaining said clamping member in both said positions.

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1. A holder adapted to releasably hold a small number of sheets having opening means along one edge thereof, comprising: base means including a substantially rigid plate-like member adapted to have said sheets supported on the upper surface thereof, said base means also including an elongated base member disposed adjacent and fixedly connected to one edge of said plate-like member; pin means fixedly secured to said base means adjacent said one edge of said plate-like member and projecting upwardly from said upper surface, said pin means being adapted to extend through the opening means formed in said sheets; clamping means mounted on said base means for releasably holding said sheets in engagement with said pin means, said clamping means including an elongated clamping member disposed adjacent and substantially parallel to said base member; hinge means connected between said clamping member and said base means for permitting said clamping member to be pivotally moved between (1) a closed position wherein the clamping member holds the sheets in engagement with the pin means and (2) an open position permitting the sheets to be removed from the pin means: said clamping member having a substantially channel-shaped cross section which opens downwardly toward said upper surface and extends over said pin means when the clamping member is in said closed position, said clamping member including opposed and substantially parallel leg portions extending longitudinally thereof, one of said leg portions being connected to said hinge means, the other leg portion comprising the free edge of said Clamping member and having a deformable clamping strip secured thereto for clamping engagement with the sheets at a position directly adjacent said pin means when the clamping member is in said closed position, said clamping member also having a pair of closely adjacent but laterally spaced narrow slots formed in the free end of said one leg portion; said hinge means including a substantially U-shaped hinge member having a center portion thereof fixedly connected to said base means and a pair of substantially parallel hinge plates disposed within planes substantially transverse to the elongated direction of said clamping member, said hinge plates being disposed within said slots, and said hinge means also including hinge pin means connected between said hinge plates and said one leg portion; said hinge pin means including a first pin member disposed within a bore formed in said one leg portion, said first pin member extending across one of said slots, and one of said hinge plates having a slot formed therein and open to an edge thereof with said one hinge plate being adapted to extend into said one slot for hingedly connecting said clamping member to said base means while permitting disconnection therebetween without requiring removal of said first pin member from said clamping member, said hinge means also including a second pin member mounted on said one leg portion of said clamping member and extending across the other slot, said second pin member extending through an opening formed in the other hinge plate for preventing disconnection of said clamping member and said base member; and over-center spring means including a plate-like leaf spring coacting between said clamping member and said base means for resiliently maintaining said clamping member in both said positions.
 2. A holder according to claim 1, wherein said leaf spring is of a cantilevered type and is disposed within the U-shaped hinge member between said pair of hinge plates.
 3. A holder according to claim 2, wherein said leaf spring has one end thereof positioned directly adjacent the center portion of said U-shaped hinge member and fixedly interconnected to said base member, the other end of said leaf spring being free and being disposed in resilient engagement with the free end of said one leg portion of said clamping member.
 4. A holder according to claim 1, wherein said base member has an elongated flange fixedly secured to the free edge thereof and projecting longitudinally of said base member, and said clamping member having an elongated flange projecting outwardly from the center portion thereof adjacent the junction with said one leg portion, said elongated flange being interconnected to said one leg portion by means of an undercut concave surface, said elongated flange on said clamping member functioning as a stop member and being disposed in abutting engagement with the upwardly directed flange on the edge of said base member when said clamping member is in said open position, the upwardly directed flange on said base member extending toward said one leg portion and being disposed in substantial engagement with said concave surface when said clamping member is in said open position.
 5. A holder according to claim 1, further including a pair of removable plate-like cover members fixedly but removably secured to the opposite ends of said base member, said cover members being disposed directly adjacent the opposite ends of said clamping member and projecting upwardly to substantially close the opposite ends of the recess defined by the downwardly directed channel-shaped clamping member when the clamping member is in the closed position.
 6. A holder according to claim 1, wherein the elongated base member and the elongated clamping member are both extruded from aluminum.
 7. A holder according to claim 1, wherein the base member includes an upwardly projecting rib extending longitudinally thereof, said rib being disposed substantially midway between the opposite longItudinal edges of said base member, said base member further having an upwardly directed flange extending longitudinally along one edge thereof; said hinge means including a pair of said U-shaped hinge members fixedly secuted to said base member adjacent the opposite ends thereof, said U-shaped hinge members being disposed in engagement with the upper surface of said base member in the region defined between said rib and said upwardly projecting flange; and said plate-like member overlapping the upper surface of said base member with the edge of said plate-like member being disposed substantially in abutting engagement with said rib.
 8. A holder according to claim 1, wherein said base means includes a resilient pad fixedly secured to the bottom surface of said plate-like member, and cover means hingedly connected to said base means along the longitudinal edge thereof opposite said clamping member, said cover means being swingably movable into a position wherein it overlies said plate-like member for substantially covering same.
 9. A holder according to claim 1, wherein said first pin member comprises a hollow axially split spring pin.
 10. A holder adapted to releasably hold a small number of sheets having opening means along one edge thereof, comprising: base means including a substantially rigid plate-like member adapted to have said sheets supported on the upper surface thereof, said base means also including an elongated base member disposed adjacent and fixedly connected to one edge of said plate-like member; clamping means mounted on said base means for releasably holding said sheets in engagement with said plate-like member, said clamping means including an elongated clamping member disposed adjacent and substantially parallel to said base member; hinge means connected between said clamping member and said base means for permitting said clamping member to be pivotally moved between (1) a closed position wherein the clamping member holds the sheets in engagement with the plate-like member and (2) an open position permitting the sheets to be removed from the base means; said clamping member having a substantially channel-shaped cross section which opens downwardly toward said upper surface when the clamping member is in said closed position, said clamping member including opposed and substantially parallel leg portions extending longitudinally thereof, one of said leg portions being connected to said hinge means, the other leg portion comprising the free edge of said clamping member and having a clamping strip for clamping engagement with the sheets when the clamping member is in said closed position, said clamping member also having a pair of closely adjacent but laterally spaced narrow slots formed in the free end of said one leg portion; said hinge means including a substantially U-shaped hinge member having a center portion thereof fixedly connected to said base means and a pair of substantially parallel hinge plates disposed within planes substantially transverse to the elongated direction of said clamping member, said hinge plates being disposed within said slots, and said hinge means also including hinge pin means connected between said hinge plates and said one leg portion; said hinge pin means including a first pin member disposed within a bore formed in said one leg portion, said first pin member extending across one of said slots, and one of said hinge plates having a slot formed therein and open to an edge thereof with said one hinge plate being adapted to extend into said one slot for hingedly connecting said clamping member to said base means while permitting disconnection therebetween without requiring removal of said first pin member from said clamping member, said hinge means also including a second pin member mounted on said one leg portion of said clamping member and extending across the other slot, said second pin member extending through an opening formed in the other hinge plate for preventing disconneCtion of said clamping member and said base member; and over-center spring means including a plate-like leaf spring coacting between said clamping member and said base means for resiliently maintaining said clamping member in both said positions. 